HST to JST Time Converter

When it is 9:00 AM HST, it is 4:00 AM JST. Japan Standard Time (JST, UTC+9) is 19 hours ahead of Hawaii Standard Time (HST, UTC-10). There is no full 9–5 overlap between HST and JST — teams typically rotate early or late meetings.

HST to JST Conversion Table

Major Cities Using HST and JST

Hawaii Standard Time (HST): Honolulu, Hilo, Pearl Harbor.

Japan Standard Time (JST): Tokyo, Osaka, Kyoto, Yokohama.

How many hours between HST and JST?

HST is UTC-10 and JST is UTC+9, a difference of 19 hours. JST is ahead of HST. This difference can shift by an hour in either direction during Daylight Saving Time transitions — if one zone observes DST and the other doesn't, the offset narrows or widens for part of the year.

Business Hours Overlap: HST ↔ JST

Assuming a 9:00 AM – 5:00 PM workday on each side, there is no full 9–5 overlap between hst and jst — teams typically rotate early or late meetings. To visualize this instantly for any pair of cities, use the visual meeting planner or the timezone overlap finder — both highlight the green overlap window on a live timeline.

Does HST observe Daylight Saving Time?

Hawaii Standard Time (HST) is based on the Pacific/Honolulu IANA timezone. DST observance depends on the jurisdiction — for example, most of the continental US switches between standard and daylight time, while India, Japan, and most of Southeast Asia do not observe DST at all. WorldClock.lol uses the authoritative IANA timezone database, so every conversion automatically accounts for the correct DST rules on the date you're converting.

When is 9 AM HST in JST?

When it is 9:00 AM in Hawaii Standard Time (HST, UTC-10), it is 4:00 AM in Japan Standard Time (JST). For other times of day, scan the conversion table above or drop into the interactive converter to pick an exact minute. The converter handles both standard and daylight variants correctly.

How to Use This HST to JST Converter

1. Type or drag any time in the HST input above — the JST equivalent updates instantly.
2. Check the day indicator. When the converted time crosses midnight, the tool shows +1 day or −1 day so you don't book a meeting on the wrong date.
3. Copy the shareable URL to send the specific conversion to a colleague — the link preserves your exact selection.
4. Switch directions by swapping the input zones, or open JST to HST for the reverse.

Related HST Converters

• HST to EST
• HST to PST
• HST to GMT
• HST to UTC
• HST to IST
• HST to CET

Related JST Converters

• EST to JST
• PST to JST
• GMT to JST
• UTC to JST
• IST to JST
• CET to JST

More Time Tools

• All Time Zone Converters — browse every supported pair
• About HST (Hawaii Standard Time) — current time, cities, DST rules
• About JST (Japan Standard Time) — current time, cities, DST rules
• Meeting Planner — find the best time for a multi-city meeting
• Best Time to Call — optimal calling windows between any two cities
• UTC Time Now — the reference point for every conversion
• DST Schedule 2026 — every daylight-saving transition this year